Composition comprising cysteamine for improving immunity of animals

ABSTRACT

There is provided a new use of cysteamine, a salt thereof, or a composition containing cysteamine or a salt thereof, for improving immunity of animals.

The present invention relates to the use of cysteamine or acysteamine-containing composition for modulating immunity of animals,and in particular, improving immunity of vertebrate animals.

The survival of animals relies on an effective immune system. The immunesystem of animals and in particular vertebrate animals, made up of manyorgans and cells, defends the body against infection, disease andforeign substances such as viruses and bacteria. There have beenproposed various compositions for boosting the immunity of the body fortreating diseases or simply to improve the general well being of thebody. For example, some pharmaceuticals for HIV infection treat theHIV-infected patients by seeking to improve the general immunity of thepatients. However, these pharmaceuticals are not always reliable andthey tend to cause many undesirable side effects.

It is thus an object of the present invention in which the above issuesare addressed, or at least to provide a useful alternative to thepublic. The present invention provides a composition for use inmodulating the immunity of animals; the composition may be used byitself or in combination with other existing compositions orpharmaceuticals.

According to a first aspect of the present invention, there is providedthe use of cysteamine, a salt thereof, or a composition containingcysteamine or a salt thereof, for improving immunity of animals.

According to a second aspect of the present invention, there is provideda composition for improving immunity of animals, comprising cysteamine,a salt thereof, or a composition containing cysteamine or a saltthereof.

According to a third aspect of the present invention, there is providedan animal feed additive for improving immunity of animals comprising acomposition as described above.

According to a fourth aspect of the present invention, there is providedan animal feed for improving immunity of animals comprising acomposition as described above.

According to a fifth aspect of the present invention, there is provideda method of improving immunity of animals, comprising administeringcysteamine, or a salt thereof, or a composition containing cysteamine ora salt thereof, into the animals.

Improving immunity may include increasing the level of interleukin-2(IL-2) in the animals. Improving immunity may also include increasingthe level of interleukin-6 (IL-6) in the animals. In particular,improving immunity may also include stimulating production oflymphocytes in the animals. Studies have shown that a higher level ofIL-2 or IL-6 corresponds to a generally stronger immune system. It hasbeen identified that the above use is particularly effective invertebrate animals such as cattle and poultry.

Preferably, the composition may comprise 1 to 95 wt % of cysteamine, ora salt thereof, and an inclusion compound host materials compositioncomprising a stabilizer selected from a group including cyclodextrin andits derivatives. Suitably, the cysteamine-containing composition maycomprise 1 to 75 wt % of cysteamine or a salt thereof. More suitably,the cysteamine-containing composition may comprise 1 to 40 wt %cysteamine or a salt thereof.

Preferably, the cysteamine-containing composition may comprise 1 to 60wt % of the inclusion compound host materials composition. Suitably, thecysteamine-containing composition may comprise 10 to 40 wt % of theinclusion compound host materials composition. The stabilizer comprisedin the inclusion compound host materials composition may be selectedfrom a group including cyclodextrin (-CD), methyl β-cyclodextrin(M-β-CD), hydropropyl β-cyclodextrin (HP-β-CD), hydroethylβ-cyclodextrin (HE-β-CD), poly-cyclodextrin, ethyl β-cyclodextrin(E-β-CD) and branched cyclodextrin.

Preferably, the cysteamine-containing composition may comprise at leastone of fillers, disintegrants, binders, flavorings and smelling agents,and coating materials. In particular, the cysteamine-containingcomposition may comprise 1 to 20 wt % of the coating materials.Advantageously, the coating materials may be enteric, and selected froma group including cellulose acetate phthalate, starch acetate phthalate,methyl cellulose phthalate, glucose or fructose derivatives fromphthalic acid, acrylic and methacrylic copolymers, polymethyl vinylether, partly esterified substance of maleic anhydride copolymer andformogelatine.

Preferably, the cysteamine-containing composition may comprise 1 to 90wt % of the fillers. Suitably, the cysteamine-containing composition maycomprise 1 to 60 wt % of the fillers, and the fillers may be selectedfrom a group including powdered cellulose, starch and calcium sulfate.

Preferably, the cysteamine-containing composition may comprise 5 to 50wt % of the binders and the disintegrants. Suitably, thecysteamine-containing composition may comprise 15 to 35 wt % of thebinders and the disintegrants. The binders and the disintegrants may beselected from a group including hydropropyl starch, microbial alginate,microcrystalline cellulose and starch.

Preferably, the cysteamine-containing composition may comprise 0.05 to0.3 wt % of the flavoring and smelling agents for enhancing the flavorthereof.

Suitably, the cysteamine-containing composition may be formed intogranules, each of which comprises at least one layer of the coatingmaterials. The cysteamine-containing composition may preferably beformed into granules in which the cysteamine or a salt thereof isshielded from its surroundings by the inclusion compound host materialscomposition. Each of the granules of the cysteamine-containingcomposition may have a size ranging from 0.28 to 0.90 mm in diameter.The granules with this range of size can be more easily swallowed by theanimals. The cysteamine-containing composition may preferably beencapsulated by the enteric coating materials.

The cysteamine-containing composition may be used for the manufacture ofan animal feed additive. The cysteamine-containing composition may alsobe used for the manufacture of an animal feed. In particular, thecysteamine-containing composition may be adapted for oral administrationinto animals. However, cysteamine for improving immunity in animals maybe administered to animals by other means such as by direct injection.

The present invention is based on the demonstration that cysteamine or acysteamine-containing composition when administered to animals such ascows has activity in modulating immunity and in particular improvingimmunity thereof. Prior to this finding, there was no suggestion orsufficient indication that cysteamine or its variants or derivativesmight have such activity. The present invention also provides a feed anda feed additive for improving immunity of animals and a method forimproving immunity of animals.

One effect of cysteamine is described in PRC Patent Publication No. CN1358499 and International Patent Publication No. WO02/48110, the contentof which is incorporated herein. However, a previously unknown effect ofcysteamine is its effect on improving immunity of animals. The effect ofcysteamine or a cysteamine-containing composition on the immunity ofanimals is explained as follows. It is believed that cysteamine having aphysiological activity acts as a growth stimulator. Natural cysteamineis a part of coenzyme A (also know as CoA-SH or CoA) which is a coenzymepattern of pantothenic acid. In the course of metabolism, coenzyme Aacts as the carrier of dihydrosulfuryl or variants of hydrosulfurylwhich is linked with the hydrosulfuryl of coenzyme A.

Experiments performed on other animals such as pigs, poultry, fowls,goats, rabbits and fish have shown that cysteamine can depletesomatostain (SS) in the animals. This increases the level of growthhormone in the blood of the animals which at the same time raises thelevel of various other growth stimulating factors including insulin-likegrowth factor I (IGF-I), insulin, triiodothyronine (T3), trthyroxine(T4) and beta-endorphin (beta-END).

As regards the present invention, it is shown that cysteamine canimprove immunity by increasing the level of interleukin-2 (IL-2) and/orinterleukin-6 (IL-6).

IL-2 belongs to a class of soluble, regulatory proteins known ascytokines. IL-2 is a 133-amino acid glycoprotein secreted by T(H)lymphocytes and other cells following activation by antigens, mitogensand other cytokines. IL-2 stimulates the proliferation and cytotoxicityof T lymphocytes, enhances the microbicidal and cytotoxic activities ofNK cells, B-lymphocytes, macrophages and monocytes (Sule N S, Nerurkar RP, Kamath S; 2001; Interleukin-2 as a therapeutic agent; J AssocPhysicians India. 49: 897-900). It is shown that IL-2 represents animportant role in the immune system.

Studies have shown that IL-2 leads to the curtailment of HIV spreadingin HIV infected patients of all stages of HIV disease (Paredes R, LopezBenaldo de Quiros J C, Fernandez-Cruz E, Clotet B, Lane H C; 2002; Thepotential role of interleukin-2 in patients with HIV infection. AIDS Rev4(1): 36-40). IL-2 is also a promising immunotherapeutic agent mediatingthe regression of established growing cancers (Rosenberg S A. 200;Progress in the development of immunotherapy for the treatment ofpatients with cancer; J Intern Med 250(6): 462-75), metastatic melanoma,acute myelogenous leukemia and metastatic renal cell carcinoma (Atkins MB; 2002; Interleukin-2: clinical applications; Semin Oncol 29(3 Suppl7): 12-7 )in humans. However, at the time of filing this application, ithas been about fifteen years since the first positive clinical reportsof IL-2 appeared in the medical literature, ten years since moderatedose continuous infusion IL-2 was approved in Europe and five yearssince high-dose bolus IL-2 was approved for general use in the UnitedStates when IL-2 has been accepted as a standard treatment to be usedalone or in combination with chemotherapy or biotherapy in themanagement of diseases (Dillman R O. 1999. What to do with IL-2? CancerBiother Radiopharm 14(6): 423-34). It took a relatively long time beforeIL-2 has been widely accepted to be used for improving the immunity inanimals. Numerous reports have shown the immunomodulatory capabilitiesof recombinatant (rb) IL-2 on important mammary immune cell functions.In vitro and in vivo studies indicate that rbIL-2 markedly enhances theproliferation of mononuclear cells (Torre, P M. Konur P K. and Oliver SP; 1992; Proliferative response of mammary gland mononuclear cells torecombinatant bovine interleukin-2; Vet; Immunol. Immunopathol. 32:351). Studies have shown that lymphocyte populations isolated frommammary tissues increase cytotoxic and bactericidal activities followingin vitro culture with IL-2 (Shafer-Weaver K A. and Sordillo L M; 1996;Enhancing bactericidal activity of bovine lymphoid cells during theperipartument period; J. Dairy Sci. 79: 1347)(Sordillo L M. Campos M.and Babiuk L A; 1991; Antibacterial activity of bovine mammary glandlymphocytes following treatment with interluekine-2; J. Dairy Sci. 74:3370).

Turning to IL-6, IL-6 has effects on most of the major effector cells ofthe immune system, including B-lymphocytes, helper T-lymphocytes,cytotoxic T-lymphocytes, and killer cells. In B-lymphocytes cultured invitro, IL-6 is essential as a late-stage differentiation factor duringthe transition of B-cells into immunoglobulin-secreting plasma cells.Furthermore, IL-6 has been shown to augment secondary, but not primary,antibody responses in vivo. These and other data suggested that IL-6plays a major role in the development of antigen-specific immuneresponses.

Many studies have shown that IL-6 can affect the proliferation of bothperipheral and thymic T-cells. Furthermore, IL-6 can stimulate thedifferentiation of cytotoxic T-cells from the thymic precursors. IL-6has been shown to augment the activity of natural killer cells.

Recent studies on cytokine function in hematopoiesis have shown thatIL-6 cooperates with interleukin-3 (IL-3) in enhancing stem-celldifferentiation.

The role of IL-6 in vivo in inflammation is to initiate the hepaticresponses of production of acute-phase protein, such as collagenase,stromelysin, and the 72-kDa gelatinase, which enzymatically degradeconnective tissue matrix. IL-6 probably also plays a role ininflammation at local tissue sites by modulating the balance oftissue-degrading activity. (Richards C D, Scamurra R W, and Murtaugh MP. Interleukin-6. p 155-157. In: Cytokines in animal health and disease.1995. Edited by Michael J. Myers and Michael P. Murtaugh. MarcelDeckker, Inc. New York, Basel, Hong Kong)

Two kinds of effector mechanisms mediate immune responses. Specificmolecules, called antibodies, mediate some immune responses. Thesynthesis of antibodies occurs in a subset of lymphocytes calledB-lymphocytes or B-cells. Antibody-mediated immunity is called humoralimmunity. Other immune responses are mediated by cells. All types ofleukocytes in the blood participate in cell-mediated immunity. However,the specificity of the response depends upon a subset of lymphocytescalled T-lymphocytes or T-cells. The mature T-cells include HelperT-cell, cytotoxic suppressor T-cell, and memory T-cell. Helper T-cellsare required to initiate immune responses by recognizing foreignantigens and releasing factors that will promote the responses of otherlymphocytes (B-cells and T-cells) to that antigen. Cytotoxic T-cells, oncoming into contact with a target cell, deliver a “lethal hit” todestroy target cells, such as tumor or foreign cells.

Certain natural compounds have the ability to cause lymphocytes todivide. The most important of these compounds is a family of proteinscalled lectins, which are usually isolated from plants. Examples oflectins include phytohemagglutnin (PHA) which is obtainable from redkidney bean (Phaseolus vulgaris), and concanavalin A (Con A) which isobtainable from jack bean (canavalis ensiformis). These lectins have theability to specifically bind sugars on lymphocyte membrane to stimulatenucleoside incorporation, phospholipid synthesis, DNA synthesis, andcell division. PHA stimulates primarily T-cell division. These mitogenscan be used to assist in the differentiation of T-cells and, bymeasurement of the response provoked, demonstrate the ability of theT-cell system to respond to nonimmunologic stimuli (Sule N S, Nerurkar RP, Kamath S. 2001. Interleukin-2 as a therapeutic agent. J AssocPhysicians India. 49: 897-900).

The present invention teaches the use of cysteamine for improvingimmunity of animals. It is believed that cysteamine depletes the levelof somatostatin and increases the level of growth hormone, and thisresults in an increase of mitogen-induced lymphocyte proliferation. Inparticular, the present invention uses a cysteamine-containingcomposition, a compound of cysteamine enveloped in microcapsule. Thefollowing experiments seek to demonstrate the effect of cysteamine orthe cysteamine-containing composition on the immune system and immunityof animals. The experiments also seek to demonstrate the effect ofcysteamine or the cysteamine-containing composition on the concentrationof serum IL-2 and the concentration of plasma IL-6 in the animals.

The cysteamine-containing composition suitable for use in the presentinvention comprises two main ingredients of 1 to 95 wt % of cysteamine(or its salts, for example, cysteamine hydrochloride, or otherpharmaceutically acceptable acid addition salts thereof) and 1 to 80 wt% of a carrier such as inclusion compound host materials. The chemicalformula of cysteamine is HSCH₂CH₂NH₂. The term “cysteamine” referredhereinafter means cysteamine and/or its salt like compounds. Cysteamineand its salts are well known in the chemical literature.

The general chemical formula of a cysteamine salt is C₂H₇NS.X, where Xmay be HCl, H₃PO₄, bitartrate, salicylate, etc. The cysteamine used ispreferably of pharmaceutically acceptable standard and the content ofcarbon, hydrogen, nitrogen and sulfur therein are substantially 31.14 wt%, 9.15 wt %, 18.16 wt % and 41.56 wt % respectively. While the workablecontent of cysteamine in the cysteamine-containing composition rangesfrom 1 to 95 wt %, a preferable range of 1 to 75 wt % and a morepreferable range of 1 to 40 wt % of cysteamine may be used. Cysteamineis one of the main active ingredients of the cysteamine-containingcomposition. However, it has been identified that if the content ofcysteamine in the cysteamine-containing composition exceeds 95 wt %,mixing the composition with a basal feed would be rather difficult andthe effect of the composition for improving immunity of the animalswould be hindered.

The inclusion compound host materials may comprise mainly cyclodextrinand/or its derivatives which are selected from a group including methylβ-cyclodextrin (M-β-CD), hydropropyl β-cyclodextrin (HP-β-CD),hydroethyl β-cyclodextrin (HE-β-CD), polycyclodextrin, ethylβ-cyclodextrin cyclodextrin (E-β-CD) and branched cyclodextrin. Thegeneral chemical formula of cyclodextrin is (C₆O₅H₉)_(n).(C₆O₅H₉)₂ andthe structural formula is as follows.

where α-CD n=4; β-CD n=5; γ-CD n=6. (Cyclodextrin is a cyclic oligomerof alpha-D-glucopyranose.)

It is worthwhile to note that the β-CD form of cyclodextrin ispreferably used because the internal diameter of its molecule is about6-8 Å which makes it a particular suitable candidate as an inclusioncompound host material for preparation of the cysteamine-containingcomposition, which involves the use of an inclusion process. The term“cyclodextrin” referred hereinafter means cyclodextrin and/or itsderivatives. Any derivative of cyclodextrin which has the property ofstabilizing and protecting cysteamine from degradation may be used. Forexample, any one of the groups of cyclodextrin or its derivativesmentioned above may be used.

While the workable content of the inclusion compound host materials inthe cysteamine-containing composition ranges from 1 to 80 wt %, apreferable workable range of 1 to 60 wt % and a more preferable workablerange of 10 to 40 wt % of the inclusion compound host materials may alsobe used. The actual amount of the inclusion compound host materials usedwill depend on the actual content of the cysteamine used in preparingthe cysteamine-containing composition.

The cysteamine-containing composition may also comprise 1 to 90 wt % offillers although a preferable workable range of 1 to 60 wt % and a morepreferable workable range of 1 to 40 wt % of the fillers may also beused in the composition. The actual content will depend on the actualamount of cysteamine and inclusion compound host materials used. Thefillers may be selected from a group including powdered cellulose,starch and calcium sulfate (e.g. CaSO₄.2H₂O). It is to be noted that ifthe content of the fillers exceeds 90 wt % in the cysteamine-containingcomposition, the content of the main active ingredients will thus bereduced, and the cysteamine-containing composition may become lesseffective in improving immunity of the animals administered therewith.

The cysteamine-containing composition may also comprise 5 to 50 wt % ofdisintegrants and binders although a preferable workable range of 10 to40 wt % and a more preferable workable range of 15 to 35 wt % may alsobe used. The actual content will depend on the actual amount ofcysteamine, the inclusion compound host material and other ingredientsused. The binders and disintegrants may be selected from a groupincluding hydropropyl starch, microbial alginate, microcrystallinecellulose and starch. It has been identified that if the content of thedisintegrants and binders in the composition is less than 5 wt %,granules of the composition produced will lack the required hardness.

In addition, manufacturing of the composition would become verydifficult. If however the content of the disintegrants and binders ismore than 50 wt %, the resulting composition will have excessivehardness, this is especially so if the content of binders represents alarge portion of the mixture of the disintegrants and binders. This willresult in difficult absorption of the composition by the intestines ofthe animals.

The cysteamine-containing composition may also comprise 0.05 to 0.3 wt %of flavoring and smelling agents which may be a flavoring essence.

The cysteamine-containing composition may also comprise 1 to 20 wt % ofcoating materials although a preferable workable range is 1 to 15 wt %and a more preferable workable range is 2 to 10 wt %. The actual contentwill depend on the actual amount of cysteamine, the inclusion compoundhost materials and the other ingredients used. The coating materials arepreferably enteric-coated which allows dissolution in an alkalineenvironment such as in the intestines. The coating materials may be madeof and selected from a group including cellulose acetate phthalate,starch acetate phthalate, methyl cellulose phthalate, glucose orfructose derivatives from phthalic acid, acrylic and methacryliccopolymers, polymethyl vinyl ether, partly esterified substance ofmaleic anhydride copolymers, lac and formogelatine. It has beenidentified that if the content of the coating materials is less than 1wt %, granules of the composition may not be entirely covered by thecoating materials which act as a protective layer. Thecysteamine-containing composition may thus degrade before being absorbedby the intestines into the bloodstream of the animals. On the otherhand, if the content of the coating materials exceeds 15 wt %, theactive ingredients in the composition may not effectively be releasedfrom the composition. Thus, the intended modulation of immunity wouldnot be achieved.

The cysteamine-containing composition used in the present invention isin the form of small granules each of which has a preferable diameter ofsubstantially 0.28 to 0.90 mm. These granules are prepared using amicro-encapsulation method. The method involves using a macromolecularsubstance having inclusion property. The macromolecular substance may bethe inclusion compound host materials (which may comprise mainlycyclodextrin) as described above. The macromolecular substance acts as amolecular capsule to engulf the molecules of cysteamine, wherebycysteamine in the composition is protected and insulated from light,heat, air and moisture of the surroundings. The stability of cysteamineis thus preserved. The inclusion compound host materials used in themicro-encapsulation method preferably comprises a cyclic polysaccharidecompound having 6 to 12 glucose molecules, which is produced by reactingcyclodextrin glycosidtransferase and starch in the presence of Bacillus.

Various studies using acute, sub-acute and chronic toxic tests haveshown that the macromolecular substance is non-toxic. Subsequent to themicro-encapsulation process, each granule may be coated with at leastone and preferably a plurality of layers of the coating materialsdescribed above. The following provides a more detailed description of amethod of preparing the cysteamine-containing composition used in thepresent invention.

In a jacketed reactor linked with polytetrafluoroethylene and equippedwith a polytetrafluoroethylene coated stirrer, 4080 g of 75 wt %cysteamine hydrochloride solution in ethanol is added with mainlynitrogen being the atmosphere. The purity, melting point and burningresidue of the cysteamine used are preferably 98% or above, 66 to 70° C.and 0.05% or below respectively. 1200 g β-cyclodextrin is then addedinto the reactor similarly under the protection of nitrogen gas. (Thequality of β-cyclodextrin is in accordance with the requirements for afood additive. In particular, the dry basis purity is more than 98%; theweight loss by drying is less than 10.0%; the burning residue is lessthan 0.2%; the content of heavy metal is less than loppm; the arseniccontent is less than 2 ppm.) The mixture is then heated for 3 hours at40° C. Heating is then stopped and stirring continues for two hoursthereafter, products resulted therefrom are then grounded and sievedthrough a screen (e.g. 40-mesh) filter after the products have beenvacuum dried at a temperature of 40-50° C. All parts of the equipment,which may come in contact with the ingredients of the composition,should preferably be made of stainless steel.

In a tank-type mixer, 4200 g (on dry basis) of the cysteamine which hasundergone the inclusion process as described, 2600 g of the fillers, and1200 g of the disintegrants and 1700 g binders are added under theprotection of a dry surroundings. These ingredients are then thoroughlymixed, and a suitable amount of anhydrous ethanol may be added and thenmixed therewith. The resulting mixture presents a soft material withmoderate hardness, so that it can be shaped into a ball by a light holdof palms. The ball-shaped resulting mixture may then be broken up by alight touch. After the mixture is pelleted by a granulator under theprotection of nitrogen, the small granules resulting therefrom areimmediately introduced to a fluid-bed dryer, and are then dried at thetemperature of 40-50° C. in a substantially vacuum environment. Entericcoating materials are then prepared by a method with the followingformulation: cellulose acetate phthalate 8.0 g, polyethylene glycolterephthalate 2.4 ml, ethyl acetate 33.0 ml and isopropyl acetate 33.6ml. The resultant granules obtained above are uniformly coated under theprotection of nitrogen with at least one layer but preferably aplurality of layers of the enteric coating materials described above.The enteric coating materials are dissolvable only at an alkalineenvironment. This can prevent the cysteamine from prematurely escapingfrom the composition or otherwise being degraded while it is still inthe stomach of the animal. Cysteamine can adversely stimulate gastricmucous of the stomach of the animals. It is however worthwhilementioning that cysteamine has relatively little side effects otherwise.

The resultant granules of the cysteamine-containing composition are thendried completely in a vacuum dryer at a temperature of 40 to 50° C.Then, all solvents are removed. The resultant granules are then allowedto cool to room temperature, and the micro-capsula were mixed with asuitable amount of flavoring and smelling agents by a cantilever doublehelix blender. The cysteamine-containing composition is a microcapsulewith its interior having cysteamine hydrochloride and cyclodextrin, andwith its exterior coated with the enteric coating materials.

The composition produced will exhibit small granular (ormicro-particulate) shape having smooth surface, good flow property, andis easy to blend with various animal feeds. The diameter of each granuleof the composition is preferably 0.28 to 0.90 mm. The composition alsohas excellent stability. It has been found that after the composition ispackaged with sealed plastic bags and stored for one year in a cool,dark and dry place, their properties remain unchanged. Therefore, theymeet the requirements for a feed additive.

The composition having the particular construction described above has anumber of functional advantages over cysteamine by itself. Firstly, theactivity of the cysteamine contained in the composition is preservedafter it has been produced. This is important as the composition may beused as a feed additive and stored for a relatively long period of timebefore use. Secondly, the composition does not cause any noticeablegastro side effects to the animals fed therewith. Thirdly, the activityof the composition is preserved not only during storage but moreimportantly until it reaches the intestines of the animals. Fourthly,the composition can be easily administered to farm animals on alarge-scale basis cost-effectively because it can be readily mixed withany basal feed. No separate procedure or injection is needed at all.

Various experiments have been conducted to demonstrate thatadministering a feed having cysteamine or a cysteamine-containingcomposition improves immunity of animals, two experiments of which aredescribed in detail as follows.

EXPERIMENTS

Experiment 1

Background Information

One hundred Holstein cows were used in the experiment. The averageweight of the cows was about 600 kg. The cows were pre-treated with twodays of the cysteamine-containing composition as described above. Theactual experiment lasted for thirteen weeks.

Materials

The cysteamine-containing composition being in mini-pill form comprisedabout 30 wt % cysteamine together with other ingredients includingcyclodextrin which served as a stabilizer. The content of cyclodextrinin the composition was 10 wt %. The composition was prepared by WalcomBio-Chemicals Industry Limited.

Procedure

The cows were divided into a test group and a control group. The testgroup was administered with a predetermined amount of thecysteamine-containing composition via their cornmeal diet and thecontrol group was administered with no cysteamine-containingcomposition. The cows were fed three times daily at 0730, 1430 and 2130.

Blood samples were collected from the cows at the end of the fifth-weektreatment period by caudal vein puncture. 2 ml of each of the bloodsamples were centrifuged at 1500 rpm for 15 minutes. The supernatantswere pooled and stored at −20° C. for IL-2 analysis. IL-2 concentrationwas determined with IL-2 RIA Kit (produced by Institute ofRadioimmunological Technique in Military Hospital, China). The bloodsamples of the cows were also taken to determine the number ofleukocytes. IL-6 concentration was similarly determined.

Data from the test and control groups of cows were analyzed andpresented as MEAN +STANDARD ERROR. Results from the two groups of cowswere compared by T-test.

Results and Discussion

The test group of cows administered with 30 g/day of thecysteamine-containing composition had about 29% higher serumconcentration of IL-2 than that of the control group of cows. Table 1below summarizes the levels of IL-2, IL-6 and leukocytes of the twogroups of cows. TABLE 1 IL-2 Leukocytes IL-6 in (ng/ml) 10⁹/L plasma(pg/ml) Test cows 5.5 ± 0.29  9.12 309.36 ± 20.98 (n = 50) (n = 20) (n =37) Control 4.3 10.8  251.86 ± 20.98 cows (n = 50) (n = 15) (n = 39)

The 29% increase in IL-2 concentration is remarkably significantstatistically (P<0.01). It is to be noted that the number of peripheralblood leukocytes was also determined but it was found that there was nosignificant difference thereof between the test and control groups ofcows. This indicates that the high concentration of IL-2 detected wasstimulated by the cysteamine-containing composition and not by otherfactors.

The results also show that the test group of cows had a 22.8% higherplasma concentration of IL-6.

The experimental results indicate that cysteamine modulates andstrengthens the immune system of animals by increasing the levels ofIL-2 and IL-6.

Experiment 2

Background Information

Sixty-four Holstein cows were used in the experiment. The cows wererandomly divided into a test group and a control group, havingthirty-two cows in each group.

Materials

The same cysteamine-containing composition used in Experiment I was usedin this experiment.

Procedure

Starting from about twenty weeks after calving, each cow in the testgroup was administered with an initial amount of 20 g/day of thecysteamine-containing composition. The dosage of thecysteamine-containing composition was then gradually increased stepwiseuntil 60 g/day and then decreased to 30 g/day towards the end of theexperiment. The treatment with the cysteamine-containing compositionlasted for 140 days. The cows were administrated with thecysteamine-containing composition via its diet. The diet comprisescornmeal powder. The control group of cows was not administered with anycysteamine-containing composition. The cows were fed three times daily.

At the end of the 140-day experimental period, blood samples of the twogroups of cows were obtained through their caudal veins. The bloodsamples were mixed with heparin for anticoagulation. The blood sampleswere incubated in a culture medium (RMPI 1640) and the white blood cellswere isolated therefrom.

The isolated white blood cells from the samples of from the test groupof cows were divided into two batches, with one batch added withphytohemagglutnin (PHA) and the other batch added without any PHA. Thetwo batches of blood samples were then added with ³H-TdR and incubatedfor seventy-two hours.

The samples were then measured for the level of ³H-TdR incorporation byscintillation counter. The level of ³H-TdR incorporation was expressedin cpm.

The stimulation Index (SI) was then calculated based on the followingformula${SI} = \frac{{mean}\quad{cpm}\quad{in}\quad T\text{-}{cell}\quad{cultured}\quad{added}\quad{with}\quad{PHA}}{{mean}\quad{cpm}\quad{in}\quad T\text{-}{cell}\quad{cultured}\quad{without}\quad{PHA}}$

The blood samples from the control group of cows were similarly treatedand the SI thereof was calculated.

Results and Discussion

Table 2 below summarizes the average SI values of the two groups ofcows. TABLE 2 Group Index Test Control Stimulation Index (SI) 29.73 ±3.53* 21.85 ± 2.07*p < 0.05

As shown in the Table 2, the SI index of test group of cows was29.73±3.53 which is 36% higher than test of the control group of cows.The higher SI index means that there is a higher number of lymphocytesin the blood of the test group of cows indicating a generally improvedimmunity.

From the above two experiments, it is shown that cysteamine, or thecysteamine-containing composition, has effect in improving immunity ofanimals. In particular, cysteamine, or the cysteamine-containingcomposition has effects in increasing the level of interleukin-2 andalso stimulating production of T-cells.

Further studies have shown that cysteamine is particularly effective invertebrate animals in improving their immunity.

It is envisaged that with an improved immunity, farm with farm animalswill be more productive. For example, farms for raising meat-producingcattle will have a higher yield due to a lower death rate of the animalsbecause of the improved immunity thereof. It is also envisaged thatcysteamine or a cysteamine-containing composition according to thepresent invention may also be used in humans for improving immunity ofpatients. For example, cysteamine may be used in combination with aconventional AIDS pharmaceutical for treating HIV infected patients.

The contents of each of the references discussed above, including thereferences cited therein and the references listed below, are hereinincorporated herein in their entirety. It is to be noted that numerousvariations, modifications, and further embodiments are possible andaccordingly, all such variations, modifications and embodiments are tobe regarded as being within the scope of the present invention.

REFERENCES

-   1. Besedovsky H O, del Rey A. 1992.Immune-neuroendocrine circuits:    integrative role of cytokines. Front Neuroendocrinol 13(1): 61-94-   2. Auernhammer C J, Strasburger C J. 1995. Effects of growth hormone    and insulin-like growth factor I on the immune system. Eur J    Endocrinol 133(6): 635-45-   3. Khosraviani M, Davis S L. 1996. Hormonal regulation of peripheral    blood mononuclear cells in sheep. Domest Anim Endocrinol 13(2):    139-50-   4. Torre P M, Lewis M J, Ingle T L, Oliver S P. 1993. Influence of    recombinant bovine somatotropin (sometribove) on mononuclear cells    during the nonlactating period. J Dairy Sci 1993 Apr; 76(4): 983-91-   5. Szabo S, Reichlin S. 1981. Somatostatin in rat tissues is    depleted by cysteamine administration. Endocrinology 109(6): 2255-7-   6. Millard W J, Sagar S M, Badger T M, Martin J B.1983. Cysteamine    effects on growth hormone secretion in the male rat. Endocrinology    112(2): 509-17-   7. Mcguffet R K, Green H B, Basson R P, Ferguson T H. 1990.    Lactation response of dairy cows receiving bovine somatotropin via    daily injection or in a sustained-release vehicle. J Dairy Sci. 73:    763-771

1-52. (canceled)
 53. The use of cysteamine, a salt thereof, or a composition containing cysteamine or a salt thereof, for improving immunity of animals.
 54. The use according to claim 53, wherein said improving immunity includes increasing the level of interleukin-2 (IL-2) in said animals.
 55. The use according to claim 53, wherein said improving immunity includes increasing the level of interleukin-6 (IL-6) in said animals.
 56. The use according to claim 53, wherein said improving immunity includes stimulating production of lymphocytes in said animals.
 57. The use according to claim 53, wherein said animals are vertebrate animals.
 58. The use according to claim 53, wherein said composition comprises 1 to 95 wt % of cysteamine, or a salt thereof, and an inclusion compound host materials composition comprising a stabilizer selected from a group including cyclodextrin and its derivatives.
 59. The use according to claim 58, wherein said cysteamine-containing composition comprises 1 to 60 wt % of said inclusion compound host materials composition.
 60. The use according to claim 53, wherein said cysteamine-containing composition comprises at least one of fillers, disintegrants, binders, and flavorings and smelling agents.
 61. The use according to claim 53, wherein said cysteamine-containing composition comprises coating materials.
 62. The use according to claim 61, wherein said cysteamine-containing composition comprises 1 to 20 wt % of said coating materials.
 63. The use according to claim 61, wherein said coating materials are enteric.
 64. The use according to claim 61, wherein said coating materials are selected from a group including cellulose acetate phthalate, starch acetate phthalate, methyl cellulose phthalate, glucose or fructose derivatives from phthalic acid, acrylic and methacrylic copolymers, polymethyl vinyl ether, partly esterified substance of maleic anhydride copolymer and formogelatine.
 65. The use according to claim 60, wherein said cysteamine-containing composition comprises 1 to 90 wt % of said fillers.
 66. The use according to claim 60, wherein said fillers are selected from a group including powdered cellulose, starch and calcium sulfate.
 67. The use according to claim 60, wherein said cysteamine-containing composition comprising 5 to 50 wt % of said binders and said disintegrants.
 68. The use according to claim 60, wherein said binders and said disintegrants are selected from a group including hydropropyl starch, microbial alginate, microcrystalline cellulose and starch.
 69. The use according to claim 60, wherein said cysteamine-containing composition comprises 0.05 to 0.3 wt % of said flavoring and smelling agents for enhancing the flavor thereof.
 70. The use according to claim 61, wherein said cysteamine-containing composition is formed into granules, each of which comprises at least one layer of said coating materials.
 71. The use according to claim 58, wherein said cysteamine-containing composition is formed into granules in which the cysteamine or a salt thereof is shielded from its surroundings by said inclusion compound host materials composition.
 72. The use according to claim 70, wherein each of said granules of said cysteamine-containing composition has a size ranging from 0.28 to 0.90 mm in diameter.
 73. The use according to claim 63, wherein said cysteamine-containing composition is encapsulated by said enteric coating materials.
 74. The use according to claim 53 for the manufacture of an animal feed additive.
 75. The use according to claim 53 for the manufacture of an animal feed.
 76. An immunity improving composition for animals, comprising cysteamine or a salt thereof.
 77. A composition according to claim 76, wherein said improving immunity includes increasing the level of interleukin-2 (IL-2) in said animals.
 78. A composition according to claim 76, wherein said improving immunity includes increasing the level of interleukin-6 (IL-6) in said animals.
 79. A composition according to claim 76, wherein said improving immunity includes stimulating production of lymphocytes in said animals.
 80. A composition according to claim 76, wherein said animals are vertebrate animals.
 81. A composition according to claim 76, comprising 1 to 95 wt % of cysteamine, or a salt thereof, and an inclusion compound host materials composition comprising a stabilizer selected from a group including cyclodextrin and its derivatives.
 82. A composition according to claim 81, wherein said cysteamine-containing composition comprises 1 to 60 wt % of said inclusion compound host materials composition.
 83. A composition according to claim 76, wherein said cysteamine-containing composition comprises at least one of fillers, disintegrants, binders, and flavorings and smelling agents.
 84. A composition according to claim 76, wherein said cysteamine-containing composition comprises coating materials.
 85. A composition according to claim 84, wherein said cysteamine-containing composition comprises 1 to 20 wt % of said coating materials.
 86. A composition according to claim 84, wherein said coating materials are enteric.
 87. A composition according to claim 84, wherein said coating materials are selected from a group including cellulose acetate phthalate, starch acetate phthalate, methyl cellulose phthalate, glucose or fructose derivatives from phthalic acid, acrylic and methacrylic copolymers, polymethyl vinyl ether, partly esterified substance of maleic anhydride copolymer and formogelatine.
 88. A composition according to claim 83, wherein said cysteamine-containing composition comprises 1 to 90 wt % of said fillers.
 89. A composition according to claim 83, wherein said fillers are selected from a group including powdered cellulose, starch and calcium sulfate.
 90. A composition according to claim 83, wherein said cysteamine-containing composition comprising 5 to 50 wt % of said binders and said disintegrants.
 91. A composition according to claim 83, wherein said binders and said disintegrants are selected from a group including hydropropyl starch, microbial alginate, microcrystalline cellulose and starch.
 92. A composition according to claim 83, wherein said cysteamine-containing composition comprises 0.05 to 0.3 wt % of said flavoring and smelling agents for enhancing the flavor thereof.
 93. A composition according to claim 84, wherein said cysteamine-containing composition is formed into granules, each of which comprises at least one layer of said coating materials.
 94. A composition according to claim 81, wherein said cysteamine-containing composition is formed into granules in which the cysteamine or a salt thereof is shielded from its surroundings by said inclusion compound host materials composition.
 95. A composition according to claim 93, wherein each of said granules of said cysteamine-containing composition has a size ranging from 0.28 to 0.90 mm in diameter.
 96. A composition according to claim 86, wherein said cysteamine-containing composition is encapsulated by said enteric coating materials.
 97. An immunity improving animal feed additive for improving immunity of animals comprising cysteamine, a salt thereof, or a cysteamine-containing composition as defined in claim
 76. 98. An immunity improving animal feed for improving immunity of animals comprising a cysteamine, a salt thereof, or a cysteamine-containing composition as defined in claim
 76. 99. A method of improving immunity of an animal, the method comprising administering a composition comprising cysteamine or a salt thereof to the animal.
 100. The method according to claim 99, wherein improving immunity includes increasing the level of interleukin-2 (IL-2) in the animal.
 101. The method according to claim 99, wherein improving immunity includes increasing the level of interleukin-6 (IL-6) in the animal.
 102. The method according to claim 99, wherein improving immunity includes stimulating production of lymphocytes in the animal.
 103. The method in according to claim 99, wherein the composition comprises 1 to 95 wt % of cysteamine, or a salt thereof, and inclusion compound host materials comprising a stabilizer selected from a group including cyclodextrin and its derivatives
 104. The method according to claim 103, wherein said composition comprises 1 to 60 wt % of said inclusion compound host materials.
 105. The method according to claim 99, wherein said composition comprises at least one of fillers, disintegrants, binders and flavorings and smelling agents.
 106. The method according to claim 99, wherein the composition comprises coating material.
 107. The method according to claim 106, wherein the composition comprises 1 to 20 wt % of said coating material.
 108. The method according to claim 106, wherein said coating material is enteric.
 109. The method according to claim 106, wherein said coating material is selected from a group including cellulose acetate phthalate, starch acetate phthalate, methyl cellulose phthalate, glues or fructose derivatives from phthalic acid, acrylic and methacrylic copolymers, polymethl vinyl ether, partly esterified substance of maleic anhydride copolymer and formogelatine.
 110. The method according to claim 105, wherein said composition comprises 1 to 90 wt % of said fillers.
 111. The method according to claim 105, wherein said fillers are selected from a group containing powdered cellulose, starch and calcium sulfate.
 112. The method according to claim 105, wherein said composition comprises 5 to 50 wt % of said binders and said disintegrants.
 113. The method according to claim 105, wherein said binders and said disintegrants are selected from a group including hydropropyl starch, microbial alginate, microcrystalline cellulose and starch.
 114. The method according to claim 105, wherein said composition comprises 0.05 to 0.3 wt % of said flavoring and smelling agents for enhancing the flavor thereof.
 115. The method according to claim 106, wherein said composition is formed into granules, each of which comprises at least one layer of said coating material.
 116. The method according to claim 106, wherein said composition is formed into granules in which the cysteamine or a salt thereof is shielded from its surroundings by said inclusion compound host material.
 117. The method according to claim 115, wherein each of said granules of said composition has a size ranging from 0.28 to 0.90 mm in diameter.
 118. The method according to claim 108, wherein said composition is encapsulated by said coating material.
 119. The method according to claim 99, wherein the animal is a vertebrate. 